Method and apparatus for contention-based uplink data transmission

ABSTRACT

A method and apparatus for a wireless transmit receive unit (WTRU) to use a contention-based uplink communications channel, applies a rule-based restriction of access to the contention-based uplink channel that attempts to use at least one contention-free uplink channel allocation for uplink transmissions on a condition that at least one contention-free uplink channel allocation has been granted.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/324,828 filed Jul. 7, 2014, which is a continuation of U.S. patentapplication Ser. No. 12/854,495 filed Aug. 11, 2010, which issued asU.S. Pat. No. 8,774,819 on Jul. 8, 2014, which claims the benefit ofU.S. Provisional Application Ser. No. 61/233,736 filed on Aug. 13, 2009,and U.S. Provisional Application Ser. No. 61/233,359 filed on Aug. 12,2009, the contents of which are hereby incorporated by reference herein.

FIELD OF INVENTION

This application is related to wireless communications.

BACKGROUND

A dormant wireless transmit receive unit (WTRU) is a WTRU that has aradio resource control (RRC) connection to the eNodeB, has establishedradio bearers, is known on cell level, but has activated discontinuousreception (DRX) for power saving during temporary inactivity. A WTRU canbe quickly moved to this dormant “sub-state”, and the latency fortransition from dormant to active affects the quality of service (QoS).For a transition to active state, a dormant WTRU with uplinksynchronization may request uplink data transmission via transmitting aScheduling Request (SR) on the physical uplink control channel (PUCCH),in order to receive an access grant to the physical uplink sharedchannel (PUSCH). The following is an example of latency components forthe transition to the active state based on current long term evolution(LTE) specifications for an error-free SR. Assuming a periodic PUCCHconfigured for SR is scheduled every 5 ms, the average waiting time is2.5 ms. The transmission of an SR can be repeated until a schedulinggrant is received. Assuming the first SR is successfully received by theeNodeB, the scheduling grant can be sent by the eNodeB after a 3 msprocessing delay. If the grant is received in sub-frame n, the uplink(UL) data can be transmitted in sub-frame n+4, giving 3 ms for WTRUprocessing. With an uplink data transmission duration of 1 ms, the totaltransition delay can be 11.5 ms. The 3GPP LTE Advanced system aims forlatency of the dormant to active transition of 10 ms, excluding the DRXcycle. The 10 ms transition includes initial message transmission, witha message size that fits one transmission time interval (TTI). Onlyerror free transmission of data and signaling is assumed to fulfill theLTE-A target performance.

A contention-based (CB) uplink data transmission is sent only in uplinkresource blocks (RBs) that have not been used for contention-free (CF)uplink transmission. A CB transmission allows uplink synchronized WTRUsto transmit uplink data without sending a scheduling request (SR) inadvance, which reduces the latency and the signaling overhead. CB grantsare received by the WTRU in a downlink and are used to assign unusedresources on a per sub-frame basis. Thus, for small data packets, thepacket may be more efficiently transmitted on a CB channel compared to ascheduled one. The CB transmission can also include a buffer statusreport (BSR), which provides the serving eNodeB with information aboutthe amount of data available for transmission in the uplink buffers ofthe WTRU. A “regular BSR” is triggered when uplink data for a logicalchannel becomes available for transmission and either the data belongsto a logical channel with higher priority than the priorities of otherlogical channels and for which data is already available fortransmission, or there is no data available for transmission for any ofthe logical channels. There are also other types of BSRs that aretriggered by other trigger conditions.

SUMMARY

A method and apparatus for a wireless transmit receive unit (WTRU) touse a contention-based uplink communications channel, applies arule-based restriction of access to the contention-based uplink channelthat attempts to use at least one contention-free uplink channelallocation for uplink transmissions on a condition that at least onecontention-free uplink channel allocation has been granted.

Another method and apparatus for a WTRU determines size of allocatedcontention-based uplink resources granted by a communication network andsets a length of a demodulation reference signal in frequency domain tomatch the size of the allocated CB uplink resource.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingswherein:

FIG. 1A is a system diagram of an example communications system in whichone or more disclosed embodiments may be implemented;

FIG. 1B is a system diagram of an example wireless transmit/receive unit(WTRU) that may be used within the communications system illustrated inFIG. 1A;

FIG. 1C is a system diagram of an example radio access network and anexample core network that may be used within the communications systemillustrated in FIG. 1A;

FIGS. 2A and 2B show a sub-frame timing diagram for scheduling requesttransmission used to restrict access on a contention-based uplinkchannel;

FIG. 3 shows a sub-frame timing diagram for buffer status report used torestrict access on a contention-based uplink channel;

FIGS. 4A and 4B show a sub-frame timing diagram for uplink channeltransmission used to restrict access on a contention-based uplinkchannel;

FIGS. 5A and 5B show method flow charts for simultaneous transmission ona contention-based uplink and a contention-free uplink;

FIGS. 6A-6C show method flow charts for simultaneous transmission on acontention-based uplink and a random access channel;

FIG. 7 shows a method flow chart for conditional restriction of accessto the contention-based uplink channel despite receiving uplink grantsfor a sub-frame;

FIGS. 8-10 show various examples of sub-channel and resource blockassignments for a contention-based uplink channel.

DETAILED DESCRIPTION

FIG. 1A is a diagram of an example communications system 100 in whichone or more disclosed embodiments may be implemented. The communicationssystem 100 may be a multiple access system that provides content, suchas voice, data, video, messaging, broadcast, etc., to multiple wirelessusers. The communications system 100 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications systems100 may employ one or more channel access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, 102 d, a radioaccess network (RAN) 104, a core network 106, a public switchedtelephone network (PSTN) 108, the Internet 110, and other networks 112,though it will be appreciated that the disclosed embodiments contemplateany number of WTRUs, base stations, networks, and/or network elements.Each of the WTRUs 102 a, 102 b, 102 c, 102 d may be any type of deviceconfigured to operate and/or communicate in a wireless environment. Byway of example, the WTRUs 102 a, 102 b, 102 c, 102 d may be configuredto transmit and/or receive wireless signals and may include userequipment (UE), a mobile station, a fixed or mobile subscriber unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a netbook, a personal computer, a wireless sensor,consumer electronics, and the like.

The communications systems 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the core network 106, the Internet 110,and/or the networks 112. By way of example, the base stations 114 a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a HomeNode B, a Home eNode B, a site controller, an access point (AP), awireless router, and the like. While the base stations 114 a, 114 b areeach depicted as a single element, it will be appreciated that the basestations 114 a, 114 b may include any number of interconnected basestations and/or network elements.

The base station 114 a may be part of the RAN 104, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, etc. The base station 114 a and/or the base station 114 b may beconfigured to transmit and/or receive wireless signals within aparticular geographic region, which may be referred to as a cell (notshown). The cell may further be divided into cell sectors. For example,the cell associated with the base station 114 a may be divided intothree sectors. Thus, in one embodiment, the base station 114 a mayinclude three transceivers, i.e., one for each sector of the cell. Inanother embodiment, the base station 114 a may employ multiple-inputmultiple output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 116, which may beany suitable wireless communication link (e.g., radio frequency (RF),microwave, infrared (IR), ultraviolet (UV), visible light, etc.). Theair interface 116 may be established using any suitable radio accesstechnology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104 and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 116 using wideband CDMA (WCDMA). WCDMAmay include communication protocols such as High-Speed Packet Access(HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed DownlinkPacket Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.16 (i.e.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,CDMA2000 1×, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE), GSM EDGE (GERAN), and the like.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, and the like. In oneembodiment, the base station 114 b and the WTRUs 102 c, 102 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 114 band the WTRUs 102 c, 102 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 114 b and the WTRUs 102 c, 102 dmay utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A,the base station 114 b may have a direct connection to the Internet 110.Thus, the base station 114 b may not be required to access the Internet110 via the core network 106.

The RAN 104 may be in communication with the core network 106, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 102 a, 102 b, 102 c, 102 d. For example, the core network 106may provide call control, billing services, mobile location-basedservices, pre-paid calling, Internet connectivity, video distribution,etc., and/or perform high-level security functions, such as userauthentication. Although not shown in FIG. 1A, it will be appreciatedthat the RAN 104 and/or the core network 106 may be in direct orindirect communication with other RANs that employ the same RAT as theRAN 104 or a different RAT. For example, in addition to being connectedto the RAN 104, which may be utilizing an E-UTRA radio technology, thecore network 106 may also be in communication with another RAN (notshown) employing a GSM radio technology.

The core network 106 may also serve as a gateway for the WTRUs 102 a,102 b, 102 c, 102 d to access the PSTN 108, the Internet 110, and/orother networks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) andthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 112 may include wired or wireless communications networks ownedand/or operated by other service providers. For example, the networks112 may include another core network connected to one or more RANs,which may employ the same RAT as the RAN 104 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, i.e., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 1A may be configured tocommunicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram of an example WTRU 102. As shown in FIG. 1B,the WTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element 122, a speaker/microphone 124, a keypad 126, adisplay/touchpad 128, non-removable memory 130, removable memory 132, apower source 134, a global positioning system (GPS) chipset 136, andother peripherals 138. It will be appreciated that the WTRU 102 mayinclude any sub-combination of the foregoing elements while remainingconsistent with an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In another embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In yet anotherembodiment, the transmit/receive element 122 may be configured totransmit and receive both RF and light signals. It will be appreciatedthat the transmit/receive element 122 may be configured to transmitand/or receive any combination of wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 102 mayinclude two or more transmit/receive elements 122 (e.g., multipleantennas) for transmitting and receiving wireless signals over the airinterface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 106 and/or the removable memory 132.The non-removable memory 106 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a, 114 b) and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. It will be appreciated that the WTRU 102 mayacquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 1C is a system diagram of the RAN 104 and the core network 106according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116, where the WTRUs 102 a, 102 b, 102 c arerepresentative of the WTRU 102 depicted in FIG. 1B. The RAN 104 may alsobe in communication with the core network 106. The RAN 104 may includeeNode-Bs 140 a, 140 b, 140 c, though it will be appreciated that the RAN104 may include any number of eNode-Bs while remaining consistent withan embodiment. The eNode-Bs 140 a, 140 b, 140 c may each include one ormore transceivers for communicating with the WTRUs 102 a, 102 b, 102 cover the air interface 116. In one embodiment, the eNode-Bs 140 a, 140b, 140 c may implement MIMO technology. Thus, the eNode-B 140 a, forexample, may use multiple antennas to transmit wireless signals to, andreceive wireless signals from, the WTRU 102 a.

Each of the eNode-Bs 140 a, 140 b, 140 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the uplink and/or downlink, and the like. As shown in FIG. 1C, theeNode-Bs 140 a, 140 b, 140 c may communicate with one another over an X2interface.

The core network 106 shown in FIG. 1C may include a mobility managementgateway (MME) 142, a serving gateway 144, and a packet data network(PDN) gateway 146. While each of the foregoing elements are depicted aspart of the core network 106, it will be appreciated that any one ofthese elements may be owned and/or operated by an entity other than thecore network operator.

The MME 142 may be connected to each of the eNode-Bs 140 a, 140 b, 140 cin the RAN 104 via an S1 interface and may serve as a control node. Forexample, the MME 142 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and the like. The MME 142 may also provide a control planefunction for switching between the RAN 104 and other RANs (not shown)that employ other radio technologies, such as GSM or WCDMA.

The serving gateway 144 may be connected to each of the eNode Bs 140 a,140 b, 140 c in the RAN 104 via the S1 interface. The serving gateway144 may generally route and forward user data packets to/from the WTRUs102 a, 102 b, 102 c. The serving gateway 144 may also perform otherfunctions, such as anchoring user planes during inter-eNode B handovers,triggering paging when downlink data is available for the WTRUs 102 a,102 b, 102 c, managing and storing contexts of the WTRUs 102 a, 102 b,102 c, and the like.

The serving gateway 144 may also be connected to the PDN gateway 146,which may provide the WTRUs 102 a, 102 b, 102 c with access topacket-switched networks, such as the Internet 110, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and IP-enableddevices.

The core network 106 may facilitate communications with other networks.For example, the core network 106 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional land-line communications devices. For example, the corenetwork 106 may include, or may communicate with, an IP gateway (e.g.,an IP multimedia subsystem (IMS) server) that serves as an interfacebetween the core network 106 and the PSTN 108. In addition, the corenetwork 106 may provide the WTRUs 102 a, 102 b, 102 c with access to thenetworks 112, which may include other wired or wireless networks thatare owned and/or operated by other service providers.

For a contention-based (CB) uplink (UL) transmission according to themethods disclosed herein, the WTRU 102 a is synchronized for uplink andis in an RRC dormant sub-state with uplink data becoming available fortransmission in the radio link control (RLC) entity or packet datacontrol protocol (PDCP) entity, or has new uplink data with higherpriority than existing data in the WTRU's transmit buffer. The WTRU 102a then has a decision whether to send an uplink transmission using a CBchannel or a contention-free (CF) allocated channel (e.g., the physicaluplink control channel (PUCCH)). A CB transmission may be sent on a CBphysical uplink shared channel (CB-PUSCH). Since the CB-PUSCH may beused to supplement the contention-free PUCCH, the following rules areestablished for restricting access to the CB-PUSCH so that the CB-PUSCHis utilized efficiently, and the uplink transmissions of the WTRU 102 aare distributed using both the CB-PUSCH and the PUCCH. The WTRU 102 aprocessor 118 may be preconfigured to execute these rules and/or receivethese rules in signaling from the eNodeB 140 a.

A first rule based restriction on using the CB-PUSCH is based on pastand future SR occurrences. If the next PUCCH is scheduled or allocatedfor an SR within the current sub-frame or next few sub-frames (e.g.,future SR occurrences scheduled to occur within X sub-frames, X=0, 1 . .. Xmax), the WTRU 102 a may be restricted from using the CB-PUSCH.Instead, the WTRU 102 a may use the PUCCH in the allocated sub-frame totransmit the SR rather than access the CB-PUSCH, which leaves theCB-PUSCH available for the other WTRUs 102 b, 102 c. For example, asshown in FIG. 2A, the WTRU 102 a has a PUCCH scheduled at sub-frame X=2,where X=Xmax=2, and therefore, the WTRU 102 a will wait for the PUCCH totransmit the SR, rather than transmit on a CB-PUCSH. The value of Xmaxdepends on the overall latency for the SR processing, including thewaiting for the next PUCCH configured for SR, sending the SR, and/orgetting the uplink grant.

Alternatively, if the WTRU 102 a has already transmitted an SR on thePUCCH in the past few sub-frames, (e.g., within X sub-frames, X≧Xmin),and the related subsequent PUSCH grant has not yet been received, theWTRU 102 a is restricted from using the CB-PUSCH for the SR, with theexpectation that the PUSCH grant is imminent. See for example, FIG. 2B,where the WTRU 102 a transmitted on the PUCCH at sub-frame X≧Xmin=−2.Thus, the CB-PUSCH is conserved for reliance on the SR being grantedconventionally. The value of Xmin depends on the latency of the eNodeB140 a in scheduling the uplink for the WTRU 102 a.

Alternatively, the WTRU 102 a may employ parallel usage of CB-PUSCH andSR submission on PUCCH until either process results in granting ofuplink shared channel resources. Upon granting of either request, eNodeB140 a may ignore any other uplink access request in progress.

A second restriction rule for the CB-PUSCH is based on past and futurebuffer status report (BSR) occurrences. When a BSR is triggered, tosend, if at least one BSR has been transmitted (and positivelyacknowledged), and the data reported in this BSR has not beensuccessfully transmitted, the WTRU 102 a is restricted from accessingthe CB-PUSCH at least until this data is transmitted by acontention-free PUSCH transmission. Alternatively, if at least one BSRhas been transmitted (and positively acknowledged) in the past fewsub-frames (e.g., for at sub-frame Y, where Y≧Ymin), the WTRU isrestricted from using the CB-PUSCH in the current sub-frame (ortransmission time interval (TTI)). FIG. 3 shows an example where the BSRis transmitted at sub-frame Y≧Ymin=−1, thus the WTRU 102 a is prohibitedaccess to the CB-PUSCH. The value of Ymin depends on latency of theeNodeB 140 a in scheduling the uplink for the WTRU 102 a.

With respect to the CB-PUSCH interaction with a BSR and an SR, when aBSR is triggered by the WTRU 102 a, and there are no contention-freeuplink resources in the present TTI to send the BSR together with data,an SR may be triggered by the WTRU 102 a. If the WTRU 102 a transmitsdata with a BSR on the CB-PUSCH, the BSR triggering condition ismaintained and/or an SR remains pending until contention-free UL-SCHresources are granted for the WTRU. This provides a contingency for atransmission collision on the CB-PUSCH where the BSR may not be receivedsuccessfully by the eNodeB 140 a. Therefore, an SR may be transmitted onthe PUCCH in subsequent sub-frames after CB-PUSCH transmission, or a BSRis retransmitted on the next CB-PUSCH access opportunity, withconsideration to the above ruled based restrictions, until acontention-free UL-SCH resource is granted.

The following methods may be implemented by the WTRU 102 a with respectto the CB-PUSCH interaction with a BSR. Buffer status reporting iscontrolled by a radio resource control (RRC) entity of the WTRU 102 a,by configuring BSR timers. A timer retxBSR-Timer is used to trigger aRegular BSR, and a timer periodicBSR-Timer is used to trigger a PeriodicBSR upon timer expiration. If the WTRU 102 a transmits data with a BSRon the CB-PUSCH, all triggered BSRs may be cancelled and the WTRU 102 ashould start or restart the timer periodicBSR-Timer (except when the BSRis a truncated BSR), and start or restart the Regular BSR timerretxBSR-Timer. In this way, a BSR may not be transmitted on the CB-PUSCHin subsequent sub-frames until either the timer periodicBSR-Timer or thetimer retxBSR-Timer expires.

Alternatively, if the WTRU 102 a transmits data with BSR on theCB-PUSCH, the regular BSR triggering condition may not be cancelleduntil the contention-free UL-SCH resources are granted for the WTRU. Inthis way, the BSR can be retransmitted on the CB-PUSCH in subsequentsub-frames whenever there are valid contention-based uplink grants.

In another alternative, if the WTRU 102 a transmits data with BSR on theCB-PUSCH, all triggered BSRs maybe cancelled, and the WTRU should startor restart a new CB timer retx-CB-BSR-Timer in addition to setting ofthe timer periodicBSR-Timer and the timer retxBSR-Timer as set forthabove. The value of the timer retx-CB-BSR-Timer should be no less thanone and no greater than the value of timers retxBSR-Timer and/orperiodicBSR-Timer. For example, to ensure that the value of the timerretx-CB-BSR-Timer remains no greater that the value of timerretxBSR-Timer, the timer retx-CB-BSR-Timer may be reset in response to areset of the timer retxBSR-Timer. In this way, the BSR will not betransmitted on CB-PUSCH in subsequent sub-frames until the timerretx-CB-BSR-Timer expires.

The restriction on using the CB-PUSCH for the WTRU 102 a may also bewindow based with respect to recent transmissions on the PUSCH and theCB-PUSCH as follows. If the WTRU 102 a has transmitted data on at leastone PUSCH in the past few K sub-frames (i.e., the window size is Ksub-frames, where K is a positive integer), then the WTRU 102 a isrestricted from accessing the CB-PUSCH in the current sub-frame (TTI).FIG. 4A shows an example of the WTRU 102 a having transmitted on thecontention-free PUSCH within the window of K sub-frames, and therefore,the WTRU 102 a is prohibited access to the CB-PUSCH. Alternatively, ifat least one CB-PUSCH transmission by the WTRU 102 a has occurred in thepast K sub-frames, then the WTRU 102 a is restricted from accessing theCB-PUSCH in the current sub-frame (or TTI). FIG. 4B shows an example ofthe WTRU 102 a having transmitted on the CB-PUSCH within K sub-frames,such that access to the CB-PUSCH is prohibited.

The WTRU 102 a may also monitor the type of uplink load for determiningwhether to use CB-PUSCH. For example, the WTRU 102 a may gatherstatistics of uplink contention-based resources usage as received on adownlink system information block (SIB) or a new common control element(CCE). As another example, the WTRU 102 a may monitor statistics onuplink contention-free resource usage. The WTRU may derive thisinformation by monitoring the PDCCH with a cyclic redundancy check (CRC)scrambled by contention-based radio network temporary identifiers(CB-RNTIs) (i.e., a number of used contention-free resource blocks (RBs)is equal to the total number of RBs, excluding RBs used for PUCCH, minusthe number of contention-based RBs). Based on the monitored uplink loadtypes of the WTRU 102 a and/or the other WTRUs 102 b, 102 c using uplinkresources of the same serving cell/RAN 104, the WTRU 102 a may determinea probability for the WTRU 102 a to access the CB-PUSCH and then decideto use the CB-PUSCH based on the probability of access. Table 1summarizes the above described rules for restriction of CB-PUSCHtransmissions.

TABLE 1 CB-PUSCH Access Restriction Rules SR CB-PUSCH access prohibitedif SR scheduled for PUCCH in sub-frame X, where 0 ≦ X ≦ Xmax; or if SRrecently transmitted in PUCCH in previous sub-frame X, where Xmin ≦ X <0. SR/ WTRU sends both a CB-PUSCH transmission and an SR on UL-SCHPUCCH. eNodeB grants one of the requests, and ignores Grant any otherpending requests. BSR CB-PUSCH access prohibited if BSR transmitted butrelated data reported is not yet transmitted; or if at least one BSRrecently transmitted in previous sub-frame Y, where Ymin ≦ Y < 0. PUSCH/CB-PUSCH access prohibited if data transmitted recently CB- on PUSCH orCB-PUSCH within past K sub-frames. PUSCH WTRU determines amount ofcontention-free resources used UL Load and/or contention-based resourcesbeing used in the uplink, and assesses whether to access CB-PUSCH.

In another embodiment, the RB location and the number of RBs used forCB-PUSCH are controlled to reduce the blind decoding complexity at theeNodeB 140 a. The WTRU 102 a may be granted contention-based uplinkresources via the PDCCH, where the grant is in terms of a number of RBsallocated for the uplink transmission. A fixed number of RBs may be usedby the WTRU 102 a for CB-PUSCH transmissions. For example, the fixednumber can be 1 RB, or 1 RB group (RBG), or multiple RBs. Alternatively,a set of fixed number of RBs may be used. For example, a set of fixednumber of RBs can be {1 RB, 2 RBs}. In this example, the WTRU 102 a maychoose to use one of the fixed numbers (1RB or 2RBs) based on: (a) theamount and/or priority of its uplink data; (b) the WTRU class for WTRU102 a; and/or (c) the radio link condition for the WTRU 102 a (such aspath loss) in the uplink. Another possible way to control the number ofRBs is by respectively assigning a CB-RNTI to each unique number of RBs.Thus, the WTRU 102 a may be restricted to a fixed number of RBs forCB-PUSCH by being configured with a subset of CB-RNTIs associated withthe desired set of fixed number of RBs. Available CB-PUSCH resources maybe partitioned by CB-RNTIs, such that each WTRU 102 a, 102 b, 102 c maybe configured for access associated with one or more CB-RNTIs. Some ofthe WTRUs 102 a, 102 b, 102 c may therefore have more accessopportunities on the CB-PUSCH than others. The WTRU 102 a may receiveCB-RNTI grants on the PDCCH where each grant may offer a differentnumber of RBs. Therefore, the WTRU 102 a may receive a larger or asmaller grant than the other WTRUs 102 b, 102 c. The WTRU 102 a mayaccess specific CB-RNTIs configured with dedicated signaling, or may bebased on WTRU access service classes.

In yet another alternative method, the eNodeB 140 a dynamically sets thenumber of allocated RBs for CB-PUSCH operation according to the uplinktraffic load. In times of light uplink activities, more RBs may beassigned for CB-PUSCH. To avoid increasing the PDCCH signaling overheaddue to dynamic assignment of CB-PUSCH RBs, the eNodeB 140 a may definefixed locations for RBs through RRC signaling. Dynamic assignment of RBsis not necessary due to the fact that different WTRUs have differentfrequency of selectivity over multiple RBs (i.e., an RB that isfavorable for one WTRU may be unfavorable for another). WTRU.

In another embodiment, rule-based methods control simultaneoustransmission of the CB-PUSCH and other uplink channels. The LTEspecifications require that uplink control feedback information, such aschannel quality index (CQI), precoding matrix index (PMI), rank index(RI) and acknowledge/negative acknowledge (ACK/NACK) signals, betransmitted on the PUSCH scheduled by a cell RNTI (C-RNTI) or asemi-persistent scheduling C-RNTI (SPS-C-RNTI) when a PUSCH is present.For aperiodic reporting of control information, the PUSCH is used, whileperiodic reporting of control feedback information occurs on the PUCCH.In this embodiment, the decision regarding whether uplink controlfeedback information should be transmitted on the CB-PUSCH may berule-based. FIG. 5A shows a first variation of this rule-based method,in which uplink control information is divided between the PUCCH and theCB-PUSCH. In this variation, the control feedback information for theWTRU 102 a, such as CQI, PMI, RI, and ACK/NACK, is always transmitted onthe PUCCH (502), regardless of whether the WTRU 102 a receives acontention-based uplink grant (501) successfully, while other controlinformation, such as a BSR, may be transmitted on the CB-PUSCH whengranted. FIG. 5B shows a second variation, in which the WTRU 102 a maytransmit on the CB-PUSCH depending on the type of concurrent PUCCH. Forexample, if uplink control information is transmitted on a type of PUCCHthat can transmit an SR (510), then the WTRU 102 a may cancel itsCB-PUSCH transmission (511), and transmit the SR on the PUCCH. This typeof PUCCH includes all PUCCH types defined in LTE Rel8. However, if thetype of PUCCH defined for uplink control feedback informationtransmission does not allow for an SR to be transmitted by the WTRU 102a, then the WTRU 102 a may transmit its BSR on a CB-PUSCH upon grant(512).

When the WTRU 102 a has a triggered SR or at least one pending SR, itmay transmit a RACH preamble due to the absence of a PUCCH in any TTI orif maximum number of retransmissions of a dedicated SR is reached,whereupon the WTRU 102 a cancels all pending SRs. According to anotherembodiment now described, the WTRU 102 a handles simultaneous pendingtransmissions of RACH preambles (triggered as described above) andCB-PUSCH. FIG. 6A shows a first example, where a buffer of WTRU 102 ahas a RACH preamble and uplink data and BSR ready for transmission atcondition 601, the latter awaiting a CB grant. If the WTRU 102 a with apending SR receives a valid CB uplink grant successfully at 602, theWTRU 102 a may transmit CB-PUSCH data with a BSR at 604 in sub-frame Xand cancel the RACH preamble transmission at 603 (e.g., a RACH message1) in the same sub-frame X. As a result, once the CB-PUSCH transmissionfrom this WTRU 102 a is received successfully at the eNodeB 140 a, theeNodeB 140 a may schedule the subsequent uplink transmission moreefficiently having the knowledge of the BSR. This CB-PUSCH transmissionis faster than a first uplink transmission on a RACH (e.g., a RACHmessage 3). In an alternative example shown in FIG. 6B, in response tothe CB grant 602, the WTRU 102 a may only transmit a RACH preamble at613 in a sub-frame X, but will not transmit CB-PUSCH at 614 in the samesub-frame X. FIG. 6C provides an illustration of another alternative forthis embodiment, in which the WTRU 102 a transmits a RACH preamble at623 while also transmitting a CB-PUSCH with a BSR at 624 in the samesub-frame X, in response to receiving a valid contention-based uplinkgrant successfully at 602.

In yet another alternative, when the WTRU 102 a has a triggered or apending SR, and/or has initiated a CB-PUSCH, it may transmit a RACH on acondition that a predefined maximum number of retransmissions of adedicated SR were already attempted on the PUCCH, or a BSR on theCB-PUSCH has been already sent unsuccessfully.

The WTRU 102 a may receive simultaneous types of uplink grants in asub-frame and may handle such grants as follows. As shown in FIG. 7,CB-PUSCH access by the WTRU 102 a is prohibited (710) in a sub-frame X,even if it receives a contention-based uplink grant (701), if any of thefollowing conditions occur. At condition 702, WTRU 102 a successfullyreceives an uplink grant on the PDCCH (e.g., DCI format 0) for theC-RNTI or temporary C-RNTI of the WTRU 102 a in the same sub-frame. Atcondition 703, the WTRU 102 a successfully receives an uplink grant inthe Random Access Response (RAR) in the same sub-frame X. At condition704, the WTRU 102 a successfully receives an uplink grant on the PDCCHto initialize or re-initialize SPS (e.g., for DCI format 0) for theWTRU's SPS C-RNTI in the same sub-frame X. Another condition 705 for theWTRU 102 a has a non-adaptive retransmission for transmission in thesame sub-frame X (e.g., in response to reception of NACK without uplinkgrant). At condition 706, the WTRU 102 a has a configured SPS uplinkgrant previously initialized by a PDCCH in a sub-frame previous tosub-frame X.

Next described are details on transmission format and signaling aspectsfor the CB-PUSCH. In consideration of the lack of accurate channel stateinformation, using a robust transmission scheme for CB-PUSCH isproposed. Adopting a robust transmission scheme improves CB-PUSCHcapability by increasing the success rate of the transmissions. Toachieve this, the CB-PUSCH may be limited as to the modulation schemesemployed, for example, limited to binary phase shift keying(BPSK)/quadrature phase shift keying (QPSK). Additional ways in whichrobustness can be improved is configuring the CB-PUSCH transmissionssuch that the code rate may be limited to a low code rate (such as ⅓,⅙), and/or configuring the antenna transmission scheme that it may belimited to transmit diversity, if the WTRU has more than one antenna.

Regarding signaling aspects for the CB-PUSCH, the information regardingthe transmission parameters for CB-PUSCH may be received by the WTRU 102a semi-statically and/or dynamically. With respect to semi-staticsignaling, if some fixed CB-PUSCH parameters (such as modulation andcoding schemes (MCS)) are used, then those parameters may be received bythe WTRU 102 a via broadcast or through RRC signaling. Those parametersmay also be standardized, so no signaling is needed. However, PDCCHsignaling to the WTRU 102 a is necessary as contention-based RBs aredifferent from sub-frame to sub-frame.

With respect to dynamic signaling, the details of the CB-PUSCHtransmission format may be conveyed to WTRUs through PDCCH signaling.Therefore, one of the following downlink control information (DCI)formats may be used.

In a first DCI format for the CB-PUSCH, the WTRU 102 a may receive a DCIFormat 0 as defined by LTE Rel8, which is modified to make use of unused(undefined) fields. In a first modification, the cyclic redundancy check(CRC) coding may be scrambled by a CB-RNTI. Since many fields defined inFormat 0 are not necessary for CB-PUSCH operation, they may be ignoredor used for other purposes in CB-PUSCH. Table 2 summarizes an example ofmandatory fields and unused fields for CB-PUSCH operation.

TABLE 2 CB-PUSCH Format 0 fields Field size Mandatory Fields Flag forformat0/format1A differentiation 1 bit Modulation and coding scheme andredundancy version. 5 bits If MCS is standardized or fixed, then thisfield will become unused. If only a limited set of MCS will be used forCB-PUSCH, then a truncated MCS field will be used, and the rest of theMCS bits will become unused bits. Resource block assignment and hoppingresource Defined allocation. according to type of general allocation(e.g., fixed or bandwidth dependent) Unused fields Hopping flag 1 bitNew data indicator 1 bit Transmit power control (TPC) command forscheduled 2 bits PUSCH Cyclic shift for demodulation reference signal(DM RS) 3 bits UL index 2 bits (this field only applies to time divisionduplex (TDD) operation with uplink - downlink configuration 0 and is notpresent in frequency division duplex (FDD)) Downlink Assignment Index(DAI) 2 bits (this field only applies for TDD operation with uplink-downlink configurations 1-6 and is not present in FDD). Channel qualityindicator (CQI) request 1 bit Modulation and coding scheme (MCS) andredundancy 1~5 bits version, if MCS is standardized or truncated

An alternative DCI format may be defined as a DCI Format 0A, which has areduced set of fields compared with DCI Format 0 described above. TheDCI Format 0A may be a reduced version of DCI Format 0 by elimination ofthe fields left as unused from the DCI Format 0, and thus a reducedPDCCH signaling overhead results. Table 3 summarizes an example of thefield set for the DCI Format 0A.

TABLE 3 CB-PUSCH Format 0A Fields Field Size MCS and redundancy version.5 bits If MCS is standardized or fixed, then this field is not used. Ifonly a limited set of MCS will be used for CB-PUSCH, then a truncatedMCS field will be used (less than 5 bits), and the rest of MCS bitsbecome unused. Resource block assignment and hopping Defined accordingto resource allocation type of general allocation (e.g., fixed orbandwidth dependent)

With respect to RB allocation, the DCI format 0 defined in LTE Rel-8allocates contiguously allocated uplink RBs. Since the RBs not allocatedto contention-free PUSCHs (i.e., RBs allocated for CB-PUSCH) are bynature non-contiguous, a single modified DCI Format 0 cannot allocateall CB resources. An embodiment employing one of the followingapproaches may be used for handling signaling of RB allocation forCB-PUSCH. In a first approach, since the downlink common search spacefor PDCCH is limited, the number of PDCCHs allocating CB resourcesshould also be limited. Those aforementioned unused bits (such as TPC,new data indicator (NDI), etc.) may be used together with the RBassignment, and hopping resource allocation fields may be changed toallow one reused DCI Format 0 that allocates multiple or allnon-contiguous RBs. One way to signal non-contiguous RBs is to use abitmap based RB allocation. In another approach, common search space isincreased. Multiple uplink grants with different or the same CB-RNTI(s)may be used in the same sub-frame to signal CB RBs, with each uplinkgrant allocating one or several contiguous RBs grouped according to thenon-contiguous spacing of the CB uplink grant.

In order to deal with power control for the CB-PUSCH, it is noteworthythat due to inactivity of the WTRU 102 a in a dormant sub-state, thereis no accurate reference for power control. Nonetheless, the powercontrol for CB-PUSCH is important, as unlike a RACH procedure, theprocess involved in CB-PUSCH does not rely on orthogonal preambles. Assuch, there may be interference from multiple WTRUs competing for thesame CB-PUSCH resources. In order to avoid any delay in the system whileperforming power control and defeating the main purpose of CB-PUSCH, thefollowing approaches may be implemented.

In a first example approach for power control, an open-loop powersetting procedure (without the use of a transmit power control (TPC)command) for the CB-PUSCH may be implemented. An example of such an openloop power setting is presented below in Equation 1:P _(CB) _(_) _(PUSCH)(i)=min{P _(CMAX),10 log₁₀(M _(PUSCH)(i))+P _(O)_(_) _(PUSCH)(j)+α(j)·PL+Δ _(TF)(i)}   Equation (1)where:

-   P_(CMAX) is the configured WTRU transmitted power, defined as MIN    {P_(EMAX), P_(UMAX)}, where P_(EMAX) is the maximum allowed power    configured by higher layers and P_(UMAX) is the maximum WTRU power    for the specified WTRU power class.-   M_(PUSCH)(i) is the bandwidth of the CB-PUSCH resource assignment    expressed in a number of resource blocks valid for subframe i.-   P_(O) _(_) _(PUSCH)(j) is a parameter composed of the sum of a cell    specific nominal component P_(O) _(_) _(NOMINAL) _(_) _(PUSCH)(j)    provided from higher layers for j=0 and 1 and a WTRU specific    component P_(O) _(_) _(UE) _(_) _(PUSCH)(j). A new type (i.e., for    j=3) of P_(O) _(_) _(UE) _(_) _(PUSCH)(j) may be defined for the    CB-PUSCH.-   Δ_(TF)(i) compensates the transmit power according to the MCS used    for the CB-PUSCH.-   PL is the downlink pathloss estimate calculated in the WTRU based on    reference signal (RS) power provided by higher layers and received    RS power.-   α(j) is a cell specific parameter provided by higher layers.

Alternatively, the CB-PUSCH transmission may apply the last PUSCH (orPUCCH) power level to the transmit power determined by the aboveopen-loop power control. However, the final transmit power setting needsto be adjusted according to the modulation/coding setting used for theCB-PUSCH.

Alternatively, a limited two state power ramping for CB-PUSCH may beused. If p₀ is assumed as the power level for the first attempt, in caseof failure to receive an UL-SCH grant from an earlier CB-PUSCH attempt,the WTRU 102 a may proceed with p₀+Δp for the next attempts if any,where Δp is a predefined power step.

Next described is an overall procedure for CB-PUSCH operation. TheCB-PUSCH is typically used for small data packets, and thus has alimited amount of data to transmit. For example the CB-PUSCH mightcontain only WTRU identity, BSR and a small payload. The eNodeB mayindicate, either by semi-static signaling or by a grant on the PDCCHchannel, that certain RBs are available for contention-basedtransmissions. The available RBs provide resources for one or moreWTRUs.

The MCS and transport format used for the CB-PUSCH may be standardized,semi-statically signaled by the network, or as indicated in the PDCCHgrant. The MCS and format apply to a single WTRU (e.g., WTRU 102 a)using a designated number N^(CB) _(RB) of RBs, rather than to the totalnumber of RBs identified in the grant. It is also possible thatdifferent MCSs and formats may be specified for SRs and data packets.

The WTRU 102 a may use N^(CB) _(RB) RBs for a CB uplink transmission,where the value N^(CB) _(RB) may be standardized or semi-staticallysignaled by the network. The value for N^(CB) _(RB), along with the MCSand data format, effectively determine the maximum size data packet thatmay be sent using CB resources. For the eNodeB 140 a to decode the data,all CB-PUSCHs may have transport block size and MCS that are known tothe eNodeB 140 a. If the WTRU 102 a has less data than the CB transportblock size, it needs to fill the remaining space with power headroom(PHR) information and padding bits.

When the WTRU 102 a has a triggered or pending SR (i.e., triggered bydata), for each subframe until the SR is canceled, the WTRU 102 a mayattempt to send either a contention-free SR or CB PUSCH transmission.The priority between contention-free SRs and CB transmissions may eitherbe standardized or set by the network using semi-static signaling as afunction of the network load. The following priority rules may beapplied. A first rule may be that the CB resources always get priority.Alternatively, the contention-free resources always get priority, orthey may get priority after a standardized (or semi-statically signaled)number of CB attempts fail. A third possible rule may be that the CBresources are not used if contention-free resources will be availablewithin a certain number of subframes (the number may be set to one ormore). The number of subframes may be standardized or set by the networkusing semi-static signaling as a function of the network load. Anotherpossible rule may be that the CB resources may get priority overcontention-free resources if the amount of buffered data is below athreshold. The threshold may be pre-defined or signaled by higherlayers. Alternatively, the threshold may correspond to the amount ofinformation bits that may be transmitted in a single CB transmission, ora factor thereof. Alternatively, the threshold(s) may be a function ofthe amount of resources available for the CB PUSCH (expressed forinstance in terms of RBs) or the MCS to use for CB transmissions. Inaddition to any of the above, the CB transmission may be abandoned aftera standardized or semi-statically signaled number of attempts areunsuccessful. When the WTRU 102 a needs to send the CB PUSCH, it mayselect N^(CB) _(RB) RBs from those available according to a standardizedrandom function or hash function to minimize collisions. The randomfunction should be chosen so that the sequence of selections made bydifferent WTRUs will be uncorrelated. For example, a hash function maybe selected with inputs such as a WTRU ID (e.g., the C-RNTI) and CellID.

The network may acknowledge receipt of the CB-PUSCH as follows. Ascheduling grant from the eNodeB 140 a implicitly acknowledges receiptof a CB-PUSCH because it implies that the eNodeB 140 a successfullyreceived the BSR and the data payload sent with the BSR, in a similarmanner as for a contention-free SR. With respect to ACK/NACK signaling,an acknowledgement (ACK) signal may be used to explicitly acknowledgereceipt of the CB-PUSCH, in which case the WTRU 102 a will not need totransmit additional SRs or PUSCHs while it is waiting for the schedulinggrant. It is not possible for the network (eNodeB 140 a) to send anegative acknowledgement (NACK) signal since it will have no knowledgethat the WTRU attempted to send data. Therefore, if the eNodeB isconfigured for ACK signaling to acknowledge the CB-PUSCH, the WTRU 102 ahas to be configured to distinguish between an ACK and the case of notransmission.

If the WTRU 102 a has the opportunity to send a contention-free SRbetween the time the CB-PUSCH is transmitted and the reception of an ACKor scheduling grant, the WTRU 102 a may send this contention-free SR,but the eNodeB 140 a will ignore it if the CB-PUSCH was already receivedsuccessfully. To handle a situation where the WTRU 102 a does notcorrectly decode an ACK sent by the eNodeB 140 a, the WTRU 102 a couldsend the contention-free SR and appropriate error handling is specified.This condition may be avoided by setting the number of subframes to waitfor contention-free resources to be greater than the delay betweensending a data packet and receiving an ACK for that data packet.Alternatively, the WTRU 102 a simply may not send a contention-free SRbetween the time a CB-PUSCH was transmitted and the time an ACK isexpected.

The WTRU 102 a continues to send either the contention-free SR or theCB-PUSCH according to the rules above at a specified interval until acontention-free uplink scheduling grant is received or an ACK isreceived for the CB-PUSCH and it has no more data to transmit. Theinterval for CB transmissions should be randomly selected within astandardized range, and a different interval should be selected betweeneach SR transmission. Alternatively, the interval for CB transmissionsmay be fixed, either by standardization or by semi-static signaling. Ifa CB-PUSCH is sent, the WTRU 102 a makes an independent random selectionof RBs to use, and increases the power as described above.

Next described is a sub-channelization method for the CB-PUSCH. Asdescribed above, the WTRU 102 a uses N^(CB) _(RB) RBs for a CB uplinktransmission, where N^(CB) _(RB) may be standardized or semi-staticallysignaled by the network. A method for sub-channelization of the CB-PUSCHmay be used by the WTRU 102 a that creates sub-channels from the totalnumber of available RBs for the CB-PUSCH. While specific sizes aredescribed, the scope of this embodiment is not limited to such sizeswhich could be suitably modified. FIG. 8 shows an example of a CB-PUSCHsub-channel structure, with the first two slots in the time domainshown, Slot 0 and Slot1. Sub-channels 801, 802 belong to Slot 0, andsub-channels 803, 804 are in Slot 1, and the sub-channels arenon-overlapping. Each sub-channel is defined by n RBs; in this example,n=1 for all sub-channels 801-804. Each RB is defined as having multipleresource elements (REs) (e.g., 12 REs per RB). Each sub-channel consistsof m subcarriers across one slot (e.g., m=12). Each slot is shown having7 symbols, which may be OFDM-based. One symbol in the slot may be usedto carry the reference signal (RS). For example, as shown in FIG. 8, themiddle symbol of the slot is used to carry the RS. The WTRU 102 a mayuse any one or more of the sub-channels in each slot, or may beconfigured to use a subset of the sub-channels. For example, thesub-channels 801 and 802 in FIG. 8 could be used by the WTRU 102 a forthe CB-PUSCH transmission.

The sub-channel structure may either be configured by higher layersignaling, be defined by standard specifications, or signaled by thePDCCH. If the sizes of all sub-channels are fixed, for example n RBs,then it is enough to signal the parameter n. If the sizes of thesub-channels are different, for example (n, m, k) for threesub-channels, then at least these three parameters n, m, k should besignaled.

The RS may be based on a Zadoff-Chu (ZC) sequence and the WTRU 102 a mayselect a cyclic shift of a given sequence randomly and use it as the RS.The set of cyclic shifts that may be selected by the WTRU 102 a or usedin a specific sub-channel may be restricted by configuration. It is alsopossible to allocate more resources for the RS transmission as shown inFIG. 9, where the second and sixth symbols are used to carry the RS ineach slot for the sub-channels 901-904. Here again, each sub-channelconsists of a single RB.

As shown in FIG. 10, the sizes of sub-channels may be different.Sub-channels 1001, 1002, 1004, and 1005 each consist of 2 RBs, whilesub-channels 1003 and 1006 each carry only a single RB. FIG. 10 alsoshows the possible variation as to the number of RSs and locationsacross the sub-channels, as sub-channels 1001, 1002, 1004 and 1005 eachhave on RS located in the middle OFDM symbol, but sub-channels 1003 and1006 each carry two RSs. Such variations enable the WTRUs to selectivelyaccess a particular type of sub-channel depending on the amount and typeof data that needs to be transmitted in the CB-PUSCH.

In addition to or in place of dynamic grants for CB transmissions,semi-persistently scheduled (SPS) grants for CB transmissions may bedefined. Such SPS grants for CB transmissions work in a manner similarto SPS grants for contention-free transmissions, except for thefollowing differences. The periodicity of SPS grants for CBtransmissions and the number of RBs available for CB transmissions maybe signaled to the WTRU 102 a over system information. The transmissiontime offset (in units of sub-frames) may be semi-statically configuredand also be signaled over system information. In this case, there wouldbe no need to “initiate” the recurring SPS grant with an initial SPSgrant signaled over PDCCH as in the normal SPS grant for contention-freetransmissions.

In case the transmission time offset would be based on an initial SPSgrant signaled over system information (with a special C-RNTI value), amaximum validity time (or maximum number of recurrences) should bedefined for the CB SPS grant. The WTRU 102 a may determine that the CBSPS grant is unavailable upon expiration of a timer (or counter) startedupon reception of the CB SPS grant. This approach provides someadditional protection to the network against unwanted access attemptsfrom the WTRU 102 a, in case it wants to reclaim the resources that hadbeen used for CB transmissions.

The use of SPS grants for CB transmissions benefits the network byallowing the use of CB transmissions without increasing the PDCCH loadsignificantly. Using SPS grants for CB uplink allows the WTRU 102 a tobetter predict in time the availability of access to the CB uplinkchannel. For instance, if the WTRU 102 a determines that an SPS CB grantwill be available imminently, the WTRU 102 a may then refrain frommonitoring the PDCCH in certain sub-frames for conserving batteryresources.

An uplink signal may contain Demodulation Reference Signals (DM-RS) thatare intended for channel estimation and coherent demodulation. In timedomain, the location of the DM-RS may be defined to be on a particularsymbol of each slot (e.g., the fourth OFDM-based symbol). For CB uplinkoperation, the WTRU 102 a may set the length of the DM-RS signal in thefrequency domain to match the size of the allocated resources for CBuplink operation. For example, if n RBs are allocated for CB-PUSCH, thenthe DM-RS width should also be n RBs.

With respect to the CB uplink channel processing at the eNodeB 140 a,the channel is estimated for each potential received DM-RS signal. Sincethere is no coordination among different users for using CB uplinkresources, collisions among the WTRUs are possible. Therefore, theestimated channel may be used for resolution and separation ofsimultaneous CB uplink transmissions. If two WTRUs transmit on the sameCB resources but with different DM-RS, the eNodeB 140 a may operatesimilar to handling a virtual uplink MU-MIMO as in defined by the LTEspecifications. The eNodeB 140 a may detect and decode both of the twoWTRU transmissions. A sequence similar to what is used for regular PUSCHoperation may also be used for generation of the DM-RS. In order toreduce the detection complexity at eNodeB, a few sequences may beselected and assigned for the CB uplink operation. This information maybe conveyed to the WTRU 102 a along with other CB uplinkinformation/parameters. That is, this information may be signaled viaRRC signaling (e.g., when the WTRU 102 a is configured or reconfiguredvia RRC connection), an uplink grant for the CB-PUSCH, or broadcast viaSIB.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, cache memory, semiconductormemory devices, magnetic media such as internal hard disks and removabledisks, magneto-optical media, and optical media such as CD-ROM disks,and digital versatile disks (DVDs). A processor in association withsoftware may be used to implement a radio frequency transceiver for usein a WTRU, UE, terminal, base station, RNC, or any host computer.

What is claimed is:
 1. A wireless transmit/receive unit (WTRU)comprising: receiver circuitry operable to receive a grant for aphysical uplink shared channel (PUSCH) transmission in a transmissiontime interval (TTI); transmitter circuitry operable, on a condition thatscheduling request (SR) information is to be transmitted in the TTI, totransmit the SR information on a physical uplink control channel (PUCCH)simultaneously with the transmission on the granted PUSCH; and thetransmitter circuitry further operable, on a condition thatacknowledgement (ACK) information is to be transmitted in the, totransmit the ACK information on the PUCCH simultaneously with thetransmission on the granted PUSCH.
 2. The WTRU of claim 1, whereinallocation of control information between PUCCH and PUSCH is rule based.3. The WTRU of claim 1, the transmitter circuitry further operable totransmit channel quality indicator information in a PUSCH transmission.4. The WTRU of claim 1, the transmitter circuitry further operable totransmit channel quality indicator information on the PUCCH on acondition that simultaneous transmission of PUCCH and PUSCH occurs in aTTI.
 5. A method for use in a wireless transmit/receive unit (WTRU),comprising: receiving a grant for a physical uplink shared channel(PUSCH) transmission in transmission time interval (TTI); and on acondition that scheduling request (SR) information is to be transmittedin the TTI, transmitting the SR information on a physical uplink controlchannel (PUCCH) simultaneously with the transmission on the grantedPUSCH; and on a condition that acknowledgement (ACK) information is tobe transmitted in the TTI, transmitting the ACK information on the PUCCHsimultaneously with the transmission on the granted PUSCH.
 6. The methodof claim 5, wherein allocation of control information between PUCCH andPUSCH is rule based.
 7. The method of claim 5, further comprisingtransmitting channel quality indicator information in a PUSCHtransmission.
 8. The method of claim 5, further comprising transmittingchannel quality indicator information on the PUCCH on a condition thatsimultaneous transmission of PUCCH and PUSCH occurs in a TTI.
 9. A basestation comprising: transmitter circuitry operable to transmit a grantfor a physical uplink shared channel (PUSCH) transmission in atransmission time interval (TTI) to a wireless transmit/receive unit(WTRU); receiver circuitry operable to receive scheduling request (SR)information on a physical uplink control channel (PUCCH) simultaneouslywith the PUSCH transmission on the granted PUSCH from the WTRU on acondition that the WTRU transmits the SR information in the TTI; and thereceiver circuitry further operable to receive acknowledgement (ACK)information on the PUCCH simultaneously with the PUSCH transmission onthe granted PUSCH from the WTRU on a condition that the WTRU transmitsthe ACK information in the TTI.
 10. The base station of claim 9, whereinallocation of control information between PUCCH and PUSCH is rule based.11. The base station of claim 9, the receiver circuitry further operableto receive channel quality indicator information in a PUSCHtransmission.
 12. The base station of claim 9, the receiver circuitryfurther operable to receive channel quality indicator information on thePUCCH on a condition that simultaneous transmission of PUCCH and PUSCHoccurs in a TTI.
 13. A method for use in a base station, comprising:transmitting a grant for a physical uplink shared channel (PUSCH)transmission in a transmission time interval (TTI) to a wirelesstransmit/receive unit (WTRU); receiving scheduling request (SR)information on a physical uplink control channel (PUCCH) simultaneouslywith the PUSCH transmission on the granted PUSCH from the WTRU on acondition that the WTRU transmits the SR information in the TTI; andreceiving acknowledgement (ACK) information on the PUCCH simultaneouslywith the PUSCH transmission on the granted PUSCH from the WTRU on acondition that the WTRU transmits the ACK information in the TTI. 14.The method of claim 13, wherein allocation of control informationbetween PUCCH and PUSCH is rule based.
 15. The method of claim 13,further comprising circuitry configured to receive channel qualityindicator information in a PUSCH transmission.
 16. The method of claim13, further comprising circuitry configured to receive channel qualityindicator information on the PUCCH on a condition that simultaneoustransmission of PUCCH and PUSCH occurs in a TTI.